Gas-burning torches are used in various applications for applying localized intense heat. One such application is pipe soldering. Pipe soldering involves joining together components such as two pipes or two fittings, or a pipe and a fitting, through application of solder to the joint. In order to flow solder into the joint, a torch is used to heat the joint and/or the solder directly until the solder reaches its melting point. Once the solder becomes a liquid, it can then flow into the joint and, upon cooling, join and seal the components together.
Controlled application of heat to the joint is often desirable. A user of a conventional torch can control the application of heat by moving the torch into an out of proximity to the joint, such that the joint experiences intermittent heating until a desired level of heating is achieved. Another method of managing the application of heat to the joint is adjusting the size of the torch flame. Conventional torches used in this manner include those having a body, or housing, which defines an internal cavity that contains a pressure regulator and other components. Gaseous hydrocarbon fuel is supplied to the regulator when an upstream connector of the torch is connected to an external source of the fuel. The regulator is configured to at least partially restrict gas flow in a fuel line extending downstream from the regulator within the internal cavity. An on/off valve is positioned downstream of the regulator and upstream of a burn tube connected to the body of the torch. The on/off valve is configured to permit or stop gas flow through the fuel line as the user desires. A trigger is movably coupled with the body of the torch and is used to actuate the on/off valve to permit, or prevent, fuel flow to a burn tube of the torch. A controller, which includes a rotatable knob protruding through the body of the torch, is used to control the position of the regulator and the rate of fuel flow to the burn tube, and the size of the torch flame. Pipe soldering typically requires a person to use a first hand to hold the torch and a second hand to hold the solder. The rotatable knob can be difficult or awkward to rotate, for example with the thumb of the user's hand holding the torch. In this situation, to safely adjust the torch flame, a user may be required to set down the solder and use his/her second hand to rotate the knob to control the flame. This can be inconvenient, and can decrease worker efficiency.